As a rule, I don’t believe in conspiracy theories. They tend to be tidy and selective, whereas life seems so random and messy. But the case of Cuban militant and would-be Fidel Castro assassin Luis Posada Carriles has sorely tested my convictions.

I’ve been writing about Posada for nearly a decade. I interviewed him in Aruba for a series of articles in the New York Times in 1998. He was a fugitive who had escaped from Venezuela in 1985 while awaiting trial in the 1976 bombing of a Cuban passenger plane that killed all 73 people aboard —the first deadly act of airline terrorism in the Americas. Posada has maintained his innocence, but in a rare instance of unanimity, the CIA and the FBI, as well as Venezuelan, Trinidadian and Cuban intelligence, concluded that he and fellow militant Orlando Bosch had masterminded the bombing.

Last year, I wrote an Outlook article about Posada’s surprise arrival in Miami, where he filed a claim for political asylum. Not only did this move strike many as brazen, but it also seemed incomprehensible that the Bush administration, so committed to what it calls the War on Terror, could have allowed someone of Posada’s notoriety to slip into the country.

Soon after, Homeland Security Department officials got around to arresting Posada and charging him with illegal entry. I assumed that the Justice Department would act on his self-admitted history of paramilitary attacks and extradite him somewhere, and that I’d just continue to cover his case. Instead, the government has dithered for a year and a half while Posada languishes in an immigration jail in Texas.

And I, meanwhile, have found myself an unwitting player in the tangled drama of the United States and Luis Posada.

Not long after Posada’s arrest, FBI and Homeland Security agents began to phone me, seeking information about the New York Times series. One agent came right out and asked if I’d share my research materials — as well as my copies of FBI and CIA files on Posada. “Do us a favor,” he said. “We can’t find ours.” I laughed politely, assuming it was a strained attempt at humor. But he wasn’t kidding.

In August 2003, the Miami bureau of the FBI made the startling decision to close its case on Posada.

Subsequently, according to FBI spokeswoman Judy Orihuela, several boxes of evidence were removed from the bureau’s evidence room, or the “bulky,” as it is known. Among the documents that disappeared was the original signed fax that Posada had sent to collaborators in Guatemala in 1997, complaining of the U.S. media’s reluctance to believe reports about a series of bombings in Cuba, which he hoped would scare tourists and investors away from Castro’s island.

I had shown Posada a copy of this fax during my interviews with him. The fax had been intercepted by Antonio Alvarez, a Cuban exile and businessman who had shared office space with Posada in Guatemala in 1997. Alarmed, Alvarez had notified agents from the FBI’s Miami bureau, but when they took no action, he had turned to the Times.

“If there is no publicity, the job is useless,” Posada wrote in the fax. “The American newspapers publish nothing that has not been confirmed. I need all the data from the [bombing of the] discotheque in order to try to confirm it.” It was signed “Solo,” his nom de guerre.

Posada fretted to me that the fax could cause him problems with the FBI. But he had no need to worry.

Hector Pesquera, the special agent in charge of the Miami FBI bureau at the time, showed little interest in Posada’s case. To his agents’ distress, he enjoyed socializing with Miami’s hard-line exile politicians, and denied agents’ requests for wiretaps on Bosch, known as the godfather of the paramilitary groups, as well as other militants suspected of ongoing criminal activity. Pesquera shuttered investigations into exile militants, agents say, before retiring in December 2003.

Without the materials that were removed from the evidence room, which also included cables and money transfers between Posada and his collaborators in the Cuban bombings, a criminal prosecution of Posada is severely hobbled. Orihuela, the FBI spokeswoman, explained that “the supervisory agent in charge and someone from the U.S. attorney’s office would have had to sign off” before evidence is removed and destroyed. She confirmed that the approval to dispose of the evidence was given by the case agent on Posada, who happened to be Ed Pesquera — Hector’s son.